A non-symmetrical transient frequency response can be caused by switching tuning capacitances, which may be observed with frequency modulated DCOs used in polar modulation transmitter architectures. The non-symmetrical switching transient is caused by largely different time constants for turning off and turning on the tuning capacitances in the unity (varactor) cells of a digital varactor. These varactor cells are distinguished from a varactor as voltage controlled capacitance used in VCOs. The turning off and on of the varactor cells means closing/opening the RF signal path through the capacitance by opening/closing a switch that is connected in series to the capacitance(s) which increases/decreases the effective capacitance. The non-symmetrical transient distorts the output wave form of the transmitted signal, and thus it causes degradation in signal quality parameters like Error Vector Magnitude (EVM).